Black-and-chestnut eagles are true to their name, with a black body and a chestnut breast, belly and legs. The tail is grey with a black trailing edge and white streaks. The primary feathers are grey, the secondaries are black and both are barred. The eyes are yellow and their pointed crest can be 8-10 cm long.

Juveniles have grey-white head and underparts, lighter in colour than an adult, with a black crest and streaking on breast and flanks. They reach full adult plumage after four years.

Their call is a sharp, high-pitched whistle.